Proximal Peri-implant Bone Behavior in Immediately Loaded Extra-Narrow Dental Implants: Retrospective Cohort Study.

PURPOSE: To evaluate the proximal bone behavior and 1-year survival rate of immediately loaded Ø2.9 mm narrow-diameter implants. MATERIALS AND METHODS: Eighteen immediately loaded implants were retrospectively assessed by standardized radiographic analysis at three time points: T1, immediately after placement; T2, 4-6 months post-loading; and T3, 12 months post-loading. Mesial and distal bone levels were measured relative to the implant-abutment interface at two positions: the point of bone contact with the implant surface (Alt1) and the alveolar crest (Alt2). Statistical significance was set at p < .05. RESULTS: No implant failures occurred, yielding a 100% survival rate. Within the first 6 months, significant bone remodeling was observed mainly at the lateral surface (Alt1), with losses up to 1.47 mm mesially and 1.37 mm distally, particularly in grafted sites (p = .004; p = .016). From 6 to 12 months, bone levels remained relatively stable with minimal additional changes. CONCLUSION: Within the limitations of this retrospective study, immediately loaded Ø2.9 mm narrow-diameter implants demonstrated 100% survival and stable peri-implant bone levels after 12 months. The most pronounced remodeling occurred at the lateral bone surface during the first 6 months, especially in grafted sites, followed by stability, supporting their short-term clinical predictability.